if then else error

Hi,

I've the following columns:

C1 and C2

C1 has an integer and C2 indicates whether C1 (in the origin) has null/empty/space value or has an integer value (including 0).

In case C2 would be 1 it means C1 has null/empty/space and in case C2 would be 0 it means C1 has an integer value (including 0).

IF ( C2 = 1) THEN 'ERROR' ELSE C1

in query designer I've tried the following, but I get an error:

( C2 == 1 ) * C1 / C1 + ( C2 == 0 ) * C1

- ( C2 == 1 ) * C1 / C1

it means that if C1 is a SPACE I provoke error (C1 / C1) in the query. In AO I want to get X.

Can anybody tell how to do this formula?

( C2 == 1 ) * C1 / C1 + ( C2 == 0 ) * C1

Thanks  in advance.

Regards.